SMA弹簧-摩擦支座基础隔震体系的地震响应分析

Seismic response analysis of the base isolation system using SMA spring-friction bearing

大尺寸超弹性形状记忆合金(Shape Memory Alloy,简称SMA)螺旋弹簧是一种可用于结构减振控制的阻尼器。然而,迄今为止这种超弹性阻尼器在土木工程结构隔震领域的研究较少。本文提出了一种SMA弹簧-摩擦支座(SMA Spring-Friction Bearing,简称SFB)并研究了其隔震性能。首先,在考虑材料内部相变过程的SMA本构关系模型的基础上,针对超弹性SMA弹簧的恢复力性能建立了一种便于工程应用的新的宏观现象模型。随后,推导了SFB隔震结构体系运动方程,利用MATLAB程序进行了结构地震响应的数值模拟。最后,将SFB隔震体系的地震响应与具有相同结构参数的纯摩擦支座(Pure Friction Bearing,简称PFB)隔震体系和摩擦摆(Friction Pendulum System,简称FPS)隔震体系的地震响应进行了对比分析。研究结果表明,SFB对上部结构具有良好的加速度减振效果,同时,该支座较其它两种滑动支座在降低隔震层位移峰值响应和抑制隔震支座残余位移两方面具有明显的优势。

The large-scale superelastic shape memory alloy （SMA） helical spring is a type of smart damper for vi- bration control of civil structures. However, studies on the superelastic springs for seismic isolation of structures have not been reported widely up to now. In this paper, a combined isolation device consisting of SMA spring and flat sliding bearing entitledas SMA spring-friction bearing （SFB） is developed and its seismic isolation performance is investigated. First, a new macroscopic model based on the constitutive relationship considering phase transforma- tion of SMA is established to simulate the restoring force of superelastic helical springs. Then, motion equations for a structural system isolated by SFB are derived. Next, a set of seismic analyses of the isolated structure is per- formed by using Matlab program. Finally, the seismic response of the structural system isolated by the SFB is com- pared with the response of the comparable structure isolated by the pure friction bearing （PFB） and same structureisolated by the friction pendulum system （FPS）. The results indicate that the seismic acceleration response of the superstructure can be noticeably reduced by using SFB. It is also observed that the SFB shows superior to other types of sliding bearing in reducing peak bearing displacement and residual bearing deformation after earthquake.